System and method for multicast and broadcast service

ABSTRACT

The present invention relates to a system and method for providing MultiCast and BroadCast Service (MCBCS). According to the present invention, the MCBCS system and method supports session start and data path registration procedures, join and leave procedure for providing the MCBCS with static or dynamic multicast service schemes, and supports procedures for providing to mobile stations operating in idle mode. Accordingly, the present invention enables effectively implementing the MCBCS in a wireless communication system, particularly in WiMAX system, and provides the MCBCS according to the mobile stations operating in idle mode.

CROSS-REFERENCES

The present application is a continuation of U.S. patent applicationSer. No. 12/747,507 filed on Jun. 10, 2010, which is a National StageEntry of PCT/KR2008/007397 filed on Dec. 12, 2008, and claims thepriorities of Korean Patent Application No. 10-2007-0130005 filed onDec. 13, 2007, Korean Patent Application No. 10-2007-0135664 filed onDec. 21, 2007, Korean Patent Application No. 10-2007-0135875 filed onDec. 21, 2007, and Korean Patent Application No. 10-2007-0139808 filedon Dec. 28, 2007, which are incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a wireless communication system and, inparticular, to a system and method for providing MultiCast and BroadCastService (MCBCS) in a wireless communication system.

BACKGROUND ART

Communication systems are evolving to support various multimediaservices such as broadcast, video, and message streaming services.Recently, many researches are being carried out for next generationcommunication systems to provide end users with the various types ofservices requiring different Quality of Service (QoS).

Next generation communication systems aim to provide various services byinterworking between wire/wireless networks. Herein, next generationcommunication systems are Broadband Wireless Access (BWA) technologiessuch as Wireless Broadband (WiBro) and Worldwide Interoperability forMicrowave Access (WiMAX) based on the institute of Electrical andElectronics Engineers (IEEE) 802.16 standards.

However, WiMAX does not specify any detailed mechanism in order for aservice provider to provide multimedia streaming services such asbroadcast, video, and message streaming services to users withmulticast/broadcast scheme. Accordingly, in order to implement the MCBCSin a WiMAX system, it is required to specify mechanism for providing theMCBCS to users with static and dynamic multicast service schemes,broadcast service scheme, and mechanism to establish data path forproviding the MCBCS to users, e.g. mobile stations (MSs) having mobilityand fixity with the multicast/broadcast services schemes. Furthermore,in order to provided the MCBCS in the WiMAX system, it is required toimplement mechanisms for supporting mobility of the MSs, checking thepresence of MSs within a MCBCS zone (particularly, the MSs operating inidle mode) for minimizing power consumption, and managing the MCBCSdepending on the presence of the MSs.

DISCLOSURE Technical Problem

Accordingly, an aspect of the present invention is to provide a systemand method for providing MCBCS in a wireless communication system.

Another aspect of the present invention is to provide a system andmethod for providing MCBCS that is capable of supporting session startand data path registration procedures in a wireless communicationsystem.

Further, another aspect of the present invention is to provide a systemand method for providing MCBCS that is capable of supporting a staticand a dynamic multicast service in a wireless communication system.

Also, another aspect of the present invention is to provide a system andmethod for providing MCBCS that is capable of supporting MCBCS join andleave procedures in a wireless communication system.

In addition, another aspect of the present invention is to provide asystem and method for providing MCBCS in static and dynamic multicastswithin a WiMAX system.

Also, another aspect of the present invention is to provide a system andmethod for providing MCBCS optimized to a WiMAX system in a static and adynamic multicast manners.

Further, another aspect of the present invention is to provide a systemand method for providing MCBCS to MSs operating in idle mode within aMCBCS transmission zone in a wireless communication system.

Technical Solution

According to one aspect of the present invention, there is provided amethod for supporting Multicast and Broadcast Service (MCBCS) in awireless communication system. The method includes receiving, at anAccess Service Network Gateway (ASN GW), a session start request messagefrom an MCBCS server, and transmitting the session start request messagetogether with a resource reservation and data path registration requestmessages to base stations providing the MCBCS to a mobile station;performing, at the base stations, a resource reservation and data pathregistration procedure based on the session start request message, andtransmitting a session start response message together with a resourcereservation and data path registration response messages to the ASN GW;and transmitting, at the ASN GW, the session start response message tothe MCBCS server, registering data path with the MCBCS server.

According to another aspect of the present invention, there is provideda method for providing Multicast and Broadcast Service (MCBCS) in awireless communication system. The method includes receiving, at anAccess Service Network Gateway (ASN GW), a join initiate message from amobile station to be provided with an MCBCS based on a service announceinformation after performing a data path registration procedure;transmitting, at the ASN GW, a join request message to a base stationupon receipt of the join initiate message; performing, at the basestation, a dynamic service addition procedure with the mobile stationbased on the join request message, and transmitting a join responsemessage to the ASN GW; and recognizing, at the ASN GW, an MCBCS join byreceiving the join response message.

According to further another aspect of the present invention, there isprovided a method for providing Multicast and Broadcast service (MCBCS)in a wireless communication system. The method includes receiving, at anaccess service network gateway (ASN GW), a join initiate message from amobile station; checking, at the ASN GW, if the mobile station is afirst mobile station within a multicast and broadcast service (MBS) zoneupon receipt of the join initiate message, an MCBCS content, andtransmitting a resource reservation and data path registration requestmessages according to the MCBCS content to a base station; performing,at the base station, a dynamic service addition procedure with themobile station upon receipt of the resource reservation and data pathregistration request messages, and transmitting a resource reservationand data path registration response messages to the ASN GW according tothe resource reservation and data path registration request messages;and receiving, at the ASN GW, the resource reservation and data pathregistration response messages, and updating the MCBCS.

According to yet another aspect of the present invention, there isprovided a method for providing Multicast and Broadcast Service (MCBCS)in a wireless communication system. The method includes receiving, anAccess Service Network Gateway (ASN GW), an leave message from a mobilestation to stop being provided with an MCBCS; transmitting, at the ASNGW, a leave indication message to an MCBCS server upon receipt of theleave message, receiving a leave response message from the MCBCS serveraccording to the leave indication message, and transmitting a leaverequest message to the base station according to the leave responsemessage; performing, at the base station, a dynamic service deletionprocedure with the mobile station upon receipt of the leave requestmessage, and transmitting a leave response message to the ASN GWaccording to the leave request message; and receiving, at the ASN GW,the leave response message from the base station, transmitting, if themobile station is a last mobile station within an Multicast andBroadcast Service (MBS) zone, a path deregistration request message tothe base station, receiving a path deregistration response message fromthe base station according to the path deregistration request message,transmitting a multicast tree leave message to the MCBCS serveraccording to the path deregistration response message, and leaving amulticast tree.

According to further another aspect of the present invention, there isprovided a method for providing Multicast and Broadcast Service (MCBCS)in a wireless communication system. The method includes transmitting, atan MCBCS server, when an MCBCS to be provided to a mobile stationexists, to an Access Service Network Gateway (ASN GW) a service requestmessage including an identifier of a base station providing the mobilestation with the MCBCS and a connection information of a servingnetwork; transmitting, at the ASN GW, the base station a service joinrequest message including a multicast connection identifier, serviceflow identifier, and an Internet Protocol multicast addresscorresponding to the MCBCS, upon receipt of the service request message;performing, at the base station, a dynamic service addition procedurewith the mobile station upon receipt of the service join requestmessage, and transmitting a service join response message to the ASN GWaccording to the service join request message; and recognizing, at theASN GW, the MCBCS join by receiving the service join response message.

According to further another aspect of the present invention, there isprovided a method for supporting Multicast and Broadcast Service (MCBCS)in a wireless communication system. The method includes detecting, at abase station, initiate entry into an idle mode of a mobile stationwithin a Multicast and Broadcast Service (MBS) zone by receiving aderegistration request message from the mobile station, and transmittinga path deregistration request message to an Access Service NetworkGateway (ASN GW) by detecting the initiate entry into the idle mode; andtransmitting, at the ASN GW, a path deregistration response message tothe base station upon receipt of the path deregistration requestmessage, and updating an identifier of the MBS zone and an identifier ofa serving network corresponding to the mobile station in a context ofthe mobile station.

According to yet another aspect of the present invention, there isprovided a method for supporting Multicast and Broadcast Service (MCBCS)in a wireless communication system. The method includes monitoring anumber of MCBCS mobile stations including mobile stations operating inidle mode within a Multicast and Broadcast Service (MBS) zone; anddetermining whether to provide the MCBCS, based on the number of MCBCSmobile stations.

According to still another aspect of the present invention, there isprovided a system for supporting Multicast and Broadcast Service(MCBCS). The system includes a mobile station, a base station, an AccessService network Gateway (ASN GW), an MCBCS server, and a policy server,wherein the ASN GW includes a proxy module for supporting an assignmentfunction of multicast connection identifiers and radio resources, alayer 2 security function for MCBCS contents, a management function ofthe mobile station and resources for the MCBCS, and a functioninterworking with the policy server; and a Data Path Function (DPF)module for supporting registration and deregistration of a dynamic MCBCSdata path.

Advantageous Effects

The present invention provides a system and method for providing anMCBCS in a communication in detail. The present invention provides asystem and method for providing an MCBCS for support session start, datapath registration, subscription procedures for the MCBCS, and alsosupport join and leave procedures for the MCBCS in static and dynamicmodes, and proposes detailed system and method for supporting MCBCS tothe mobile station operating in idle mode.

Also, the present invention provides a system and method for supportingan MCBCS of a WiMAX system in a dynamic mode in consideration ofcommunication environment of an MCBCS zone and mobile stations operatingin idle mode.

DESCRIPTION OF DRAWINGS

The above and other aspects, features and advantages of the presentinvention will become more apparent from the following detaileddescription when taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a diagram schematically illustrating a structure of a WiMAXsystem for providing MCBCS to an MS in communication system according toan embodiment of the present invention;

FIG. 2 is a signaling diagram illustrating a session start and data pathregistration procedure in serving ASN of a communication systemaccording to an embodiment of the present invention;

FIG. 3 is a signaling diagram illustrating a subscription procedure of aMS in a communication system to an embodiment of the present invention;

FIG. 4 is a signaling diagram illustrating an MCBCS join procedure in acommunication system according to an embodiment of the presentinvention;

FIG. 5 is a signaling diagram illustrating an MCBCS join procedure in acommunication system according to another embodiment of the presentinvention;

FIG. 6 is a signaling diagram illustrating an MCBCS leave procedure in acommunication system according to an embodiment of the presentinvention;

FIG. 7 is a signaling diagram illustrating an MCBCS leave procedure in acommunication system according to another embodiment of the presentinvention;

FIG. 8 is a signaling diagram illustrating an MCBCS join procedure in acommunication system according to another embodiment of the presentinvention;

FIG. 9 is a signaling diagram illustrating an MCBCS leave procedure in acommunication system according to another embodiment of the presentinvention;

FIG. 10 is a signaling diagram illustrating an MCBCS leave procedure ina communication system according to another embodiment of the presentinvention;

FIG. 11 is a schematically diagram illustrating a structure of a WiMAXsystem for providing MCBCS to an MS in communication system according toanother embodiment of the present invention;

FIG. 12 is a signaling diagram illustrating a procedure for supportingthe MCBCS in a communication system according to another embodiment ofthe present invention; and

FIG. 13 is a signaling diagram illustrating a procedure for supportingthe MCBCS in a communication system according to another embodiment ofthe present invention.

MODE FOR INVENTION

Preferred embodiments of the present invention will now be described indetail with reference to the annexed drawings. In the drawings, the sameor similar elements are denoted by the same reference numerals eventhough they are depicted in different drawings. In the followingdescription, a detailed description of known functions andconfigurations incorporated herein has been omitted for clarity andconciseness.

The present invention relates to communication systems, e.g., aBroadband Wireless Access (BWA) communication represented by WirelessBroadband (WiBro) or Mobile Worldwide Interoperability for MicrowaveAccess (WiMAX) based on IEEE 802.16 standards. And the present inventionprovides a system and method for providing MultiCast and BroadCastService (MCBCS) in a wireless communication system. Although the systemfor MCBCS is described in association with an IEEE 802.16 system orWiMAX system in the following description, the present invention can beapplied to other types of communication system and provided for variousother types of services.

In the following description, in order to provide user, e.g., mobilestations (MSs) having mobility and fixity with the MCBCS, the WiMAXsystem operates with session start, data path registration, andsubscription procedures for providing the MCBCS. The WiMAX systemprovides the MCBCS to the MSs with a static/dynamic multicast serviceschemes, and the present invention provides the MCBCS by supporting joinand leave the WiMAX system which provides the MCBCS to MS with thestatic/dynamic multicast service schemes, i.e., by supporting MCBCS joinand leave procedures of the MS. In the following description, the WiMAXsystem supports to provide dynamic MCBCS for the MS in which the MSenters and exits the idle mode within the service area of the system.

FIG. 1 is a diagram schematically illustrating a structure of a WiMAXsystem for providing MCBCS to an MS in communication system according toan embodiment of the present invention.

Referring to FIG. 1, the WiMAX system includes an MS 102, Base stations(BSs) (i.e. BS1 112, BS2 114, BS3 116, and BS4 118) performing as RadioAccess Station (RAS) for broadcasting or multicasting MCBCS data withintheir service areas, Access Service Network (ASN) gateways (GWs) (i.e.ASN GW1 120 and ASN GW2 130) for delivering the MCBCS contents, an MCBCSserver 140 for controlling the MCBCS and providing contents, anAuthentication Authorization Accounting (AAA) server 150 which is incharge of authentication, authorization, and accounting functions, aPolicy Function (PF) server 160 which manages communication protocolsfor providing the MCBCS, and a content provider (CP) 170 which createsand provides MCBCS contents.

Here, a service area refers to a Multicast Broadcast Service (MBS) zonein which MBS services are provided by only Media Access Control (MAC)and Physical (PHY) layers of a set of BSs. The ASNs are networks forproviding the MCBCS within the MBS zone in the WiMAX system. In thisembodiment, it is assumed that the MS 102 and BSs 112, 114, 116, and 118are communicating with each other using an Orthogonal Frequency DivisionMultiplexing (OFDM) and/or Orthogonal Frequency Division Multiple Access(OFDMA). In order to simplify the explanation, the MS 102 attemptsinitial access to the WiMAX system with the BS3 116 or BS4 118 so as toenter the WiMAX system via the BS3 116 or BS4 118. Here, the ASNcomposed of the BS3 116 and BS4 118 and ASN GW2 130 is referred to asanchor ASN which performs the initial network entry procedure with theMS 102. In this embodiment, it is also assumed that, after joining theanchor ASN, the MS 102 performs handover to the BS1 112 so as to receivethe MCBCS via the ASN composed of the BS1 112, BS2 114, and ASN GW1 120.At this time, the ASN composed of the BS1 112, BS2 114, and ASN GW1 120is called a serving ASN which is providing the MCBCS to the MS 102. Thatis, the ASN GW2 130 is the anchor ASN GW, and the ASN GW1 120 is theserving ASN GW. When the anchor ANS GW and the serving ASN GW differfrom each other, the WiMAX system supports a session start, data pathregistration, and subscription procedures of the serving ASN.

The ASN GW1 120 includes a Data Path Function (DPF) module 122 formanaging a data path of the serving ASN, a Proxy module 124 operating asa proxy of the serving ASN, and a Service Flow Authorization (SFA)module 126 for authorizing the MS 102 to receive an MCBCS flow providedvia the serving ASN. The ASN GW 130 includes a DPF module 132 formanaging a data path of the anchor ASN, a Proxy module 134 operating asa proxy of the anchor ASN, and a SFA module 136 for authorizing the MS102 to receive an MCBCS flow provided via the anchor ASN. Here, the ASNGWs 120 and 130 are integrated into respective Access Control Routers(ACRs) that control the BSs 112, 114, 116, and 118.

The MCBCS server 140 includes a content server 142 for delivering aMCBCS content provided by the content provider 170 to the ASNs, and acontroller 144 for controlling the MCBCS in order to provide the MS 102with the MCBCS content delivered by the content server 142.

The AAA server 150 performs authentication, authorization, andaccounting functions on the MS 102 and the content provider 170 underthe support of the ASN GWs 120 and 130 and MCBCS server 140. The PFserver 160 supports resource assignment and reservation in accordancewith communication protocols associated with provision of the MCBCS. Thecontent provider 170 creates MCBCS contents associated with variousMCBCSs such as a location-based service, a video and audio service,Internet web service, a voice and video communication service; andtransmits the MCBCS contents to the MCBCS server 140. With reference tothe following tables, functions of the BSs 112, 114, 116, and 118 (i.e.RASs), ASN GWs 120 and 130 (ACRs), and MCBCS server 140 are describedhereinafter in more detail.

As shown in table 1, the content server 142 of the MCBCS server 140 isan MCBCS content server which receives an MCBCS content from the contentprovider 170 and delivers the MCBCS content to the ASN GWs 120 and 130.For instance, the content server 142 can be a location server forproviding location-based service, a video-on-demand/audio-on-demand(VoD/AoD) server for providing a Vod/AoD service, a web server forproviding an Internet web service, and a VoIP/VT server for providingvoice and video service. The content server 142 supports applicationlayer security, e.g. Digital Rights Management (DRM), and performsfunction for merging MCBCS contents provided by different contentproviders. Also, the content server 142 performs function for organizingMCBCS programs and channels for providing the MCBCS to the MS 102.

The controller 144 of the MCBCS server 140 supports for assigning anInternet Protocol (IP) multicast address for multicasting the MCBCScontent, IP multicast routing protocol and tunneling between ASN GW 120and 130 and MCBCS server 140, and layer 2 security of the MCBCS content.The MCBCS content channel is identified by the IP multicast addresswhich is identical with a Multicast Connection Identifier (MCID). Thecontroller 144 performs also the management of ASNs joined a multicastgroup, authentication and authorization to the MCBCS subscriber (i.e. MS102), supports for advertisement of the MCBCS provided by the MCBCSserver 140, management of MCBCS sessions (e.g. session informationassignment and start/end/update of session), and performs accounting onservice.

TABLE 1 Functional Entity Detail Features Remark MCBCS ContentApplication layer security DRM, etc Server Contents merging functionfrom different content provider MCBCS program and channel organizationMCBCS IP multicast address assignment controller IP multicast routingprotocol PIM-SM, PIM- support for R3 SMv6 R3 Tunneling support Layer 2security Multicast group member management MCBCS user authentication/authorization Service advertisement Session management Sessioninformation assignment, Session Start/Stop/Update support Accountingservice

Referring to table 2, the proxy modules 124 and 134 of the ASN GWs 120and 130 perform interworking with the PF server 160 for MCBCS,management of Service Flow Identifier (SFID) for MCBCS, and assignmentof static MCID and dynamic MCID for static and dynamic MCBCSs. The proxymodules 124 and 134 also support the Radio Resource Management (RRM)function for MCBCS and mapping function of transmission region to MBSzone. The proxy modules 124 and 134 also support the layer 2 securityand static and dynamic air resource assignments for MCBCS contents. Inorder to support a macro diversity, the proxy modules 124 and 134assigns the same air resource to all the BSs 112, 114, 116, and 118. Theproxy modules 124 and 134 perform also MCBCS group member management,i.e. managing the MSs joined the MCBCS group, accounting service, timesynch mechanism for supporting macro diversity, and MBS zone listmanagement.

The DPF modules 122 and 132 of the ASN GWs 120 and 130 performinterworking with the PF server 160 for MCBCS, management of SFID forMCBCS, and support R3 tunneling and IP multicast routing protocols forconnection among the ASNs, MCBCS server 140, AAA server 150, and PFserver. The DPF modules 122 and 132 perform also MCBCS dataclassification, accounting service, and Internet Group ManagementProtocol (IGMP) proxy function. The DPF modules 122 and 132 also supportstatic MCBCS data path registration/release between the ASN GWs 120 and130 and the BSs 112, 114, 116, and 118 and dynamic MCBCS. Particularly,the DPF module 132 of the anchor ASN performs IGMP Report messagetransmission function.

The SFA modules 126 and 136 of the ASN GWs 120 and 130 determine, whenreceived the MCBCS request from the MS 102, whether to permit or rejectthe MCBCS request based on the MS's Quality of Service (QoS) profileprovided by the AAA server 150. The SFA modules 126 and 136 perform alsoadmission control based on the resources available for providing theMCBCS by means of the local policy function modules (not shown) includedin the SFA modules 126 and 136. That is, when the WiMAX system providesthe MCBCS with static multicast service scheme, the SFA modules 126 and136 determines whether to admit or reject the MCBCS request of the MS102 based on the MS's QoS profile provided by the AAA server 150 at theinitial network entry and provides, when the MCBCS request is admitted,the MS 102 with the MCBCS flow.

TABLE 2 Functional entity Detail Feature Remark MCBCS proxy PFinterworking for MCBCS service The management of SFID for MCBCS StaticMCID assignment Dynamic MCID assignment MCBCS RRM function Mappingfunction of transmission region to MBS zone Layer 2 security supportStatic air resource Symbol, subchannel, assignment encoding rule, etcDynamic air resource assignment MCBCS group member management Accountingservice Time synch mechanism for macro diversity MBS zone listmanagement MCBCS DPF PF interworking for MCBCS service The management ofSFID for MCBCS R3 tunneling support IP multicast routing protocol for R3MCBCS data classification Accounting service IGMP proxy function StaticR6 MCBCS data Broadcast service, path registration/ Static multicastrelease service Dynamic R6 MCBCS Dynamic multicast service DPF IGMPReport message forwarding function Multicast Router Functions defined byIETF

Referring to table 3, in order for the BSs 112, 114, 116, and 118, i.e.RASs for MBS data transmission on the MAC/PHY layers, to provide MCBCSto the MS 102; a MAC control module (not shown) of the RAS perform MBSzone support and MBS RRM function on the MAC layer; a MAC data module(not shown) supports the MBS MAP Information Element (MBS_MAP_IE),MBS_MAP, MBS_DATA_IE, and MCIDs on the MAC layer; and a PHY modulesupports MPS_MAP_IE, MBS_MAP, and MBS RRM Function on the PHY layer.

TABLE 3 Functional Entity Detail Features Remark MAC(Control plane) MBSzone support MBS RRM Function MAC(Data plane) MBS_MAP_IE MBS_MAPMBS_DATA_IE Multicast CIDs PHY MBS_MAP_IE MBS RRM Function MBS_MAP Synch

Referring to table 4, in order for the WiMAX system to provide the MCBCSusing the multicast/broadcast service schemes, the MCBCS server 140 isconfigured such that its content server 142 supports MCBCS program (agroup of MCBCS Content Channels) and Channel organization function, andthe controller 144 supports IP multicast address assignment forproviding MCBCS, IP multicast routing protocol and tunneling forconnection between the ASNs and MCBCS server 140, advertisement of theMCBCSs provided by the MCBCS server 140, and session management forMCBCS. Here, the session management is performed per MCBCS content butnot per MS. Also, the ASN GWs 120 and 130 are configured such that theirproxy modules 124 and 134 support management of SFID for MCBCS, performassignment of MCID and static air resource, control mapping function oftransmission region to MBS zone and time synch mechanism for supportingmacro diversity, and perform MBS zone list management; and DPF modules122 and 132 support MCBCS data classification and static MCBCS data pathregistration/release between the ASN GWs 120 and 130 and BSs 112, 114,116, and 118. In the meantime, the BSs 112, 114, 116, and 118 areconfigured such that the MAC control module supports MBS zone on the MAClayer; the MAC data module supports time sync mechanism for macrodiversity, MBS_MAP_IE, MBS_MAP, MBS_DATA_IE, and MCIDs on the MAC layer;and the PHY module supports MBS_MAP_IE and MBS-MAP Synch on the PHYlayer.

TABLE 4 Network entity Functional entity Functions MCBCS server MCBCScontent MCBCS program and server channel organization MCBCS controllerIP multicast address assignment IP multicast routing protocol supportfor R3 Service advertisement Session management (Not per MS, but perMCBCS content) ACR MCBCS Proxy Management of SFID for MCBCS Static MCID,Air resource assignment by EMS Mapping function of transmission regionto MBS zone Time sync mechanism for macro diversity MBS zone listmanagement MCBCS DPF MCBCS data classification Static MCBCS data pathregistration/release RAS MAC(control plane) MBSMBS zone support MAC(dataplane) Time sync mechanism for macro diversity MBS_MAP_IE MBS_MAPMBS_DATA_IE Multicast CIDs PHY MBS_MAP_IE MBS_MAP Synch

Referring to table 5, in order for the WiMAX system to provide the MCBCSin static multicast service scheme, the MCBCS server 140 is configuredsuch that the content server 142 supports application layer security,and the controller 144 performs authentication/authorization, sessionmanagement for MCBCS user, e.g. MS 102, and accounting for MCBCS. Also,the ASN GWs 120 and 130 are configured such that their proxy modules 124and 134 perform assignment of static MCID and static air resource, theserving ASN's DPF module 122 performs IGMP proxy function, and theanchor ASN's DPF module 132 performs IGMP report message transmissionfunction.

TABLE 5 Network entity Functional entity Additional functions MCBCSserver MCBCS content Application layer security server MCBCS controllerMCBCS user authentication/authorization Session management per MSAccounting service ACR MCBCS proxy Static MCID, Air resource assignmentby MCBCS proxy Accounting service MCBCS DPF IGMP proxy function AnchorDPF IGMP report message forwarding function RAS MAC — PHY —

Referring to table 6, in order for the WiMAX system to provide the MCBCSin dynamic multicast service scheme, the MCBCS server 140 is configuredsuch that the content server 142 performs contents merging function fromdifferent content providers, and the controller 144 supports layer 2security and performs multicast group member (i.e. ASNs) management.Also, the ASN GWs 120 and 130 are configured such that their proxymodules 124 and 134 perform assignment of dynamic MCID and dynamic airresource, support layer 2 security, perform management of multicastgroup member (i.e. MSs joined the MCBCS group) and MCBCS RRM functionand PF interworking for MCBCS; and their DPF modules 122 and 132 supportdynamic MCBCS data path registration/release. In the meantime, the BSs112, 114, 116, and 118 (i.e. RASs) support layer 2 security and MBS RRMfunction for the MCBCS contents on the MAC layer, and perform MBS RRMfunction on the PHY layer.

TABLE 6 Network entity Functional entity Additional functions MCBCSserver MCBCS content Contents merging function server from differentcontent provider MCBCS controller Layer 2 security support multicastgroup member management ACR MCBCS proxy Dynamic MCID, Air resourceassignement by MCBCS proxy Layer 2 security support multicast groupmember management MCBCS RRM function PF interworking for MCBCS serviceMCBCS DPF Dynamic MCBCS data path registration/release RAS MAC Layer 2security support MBS RRM function PHY MBS RRM function

The proxy modules 124 and 134 of the ASN GWs 120 and 130 control the MS102 joining and leaving the anchor ASN or the serving ASN and MCBCSsession bearer establishment, assign resources related to MCBCS (i.e.MCID), create MBS security keys for air interface encryption, supportMCBCS charging, and maintain ASN GW list listing ASN GWs belonged to theMBS zone.

The DPF modules 122 and 132 of the ACRs supports MCBCS bearerestablishment and release, joining and leaving MCBCS, MCBCS datatransmission and classification, MCBCS charging, counting in order todynamical bearer establishment and release, managing movement of the MS102 in the MCBCS for the interface between the BSs (112, 114, 116, and118 and the ASN GWs 120 and 130 and the interface among the ASN GWs 120and 130 and MCBCS server 140, AAA server 150, and PF server 160, andmulticast router function.

The content server 142 of the MCBCS server 140 receives MCBCS contentfrom the content provider 170 and distributes the MCBCS content to theMS 102 through WiMAX network, repacks data from the content provider 170for properly transporting in the WiMAX network, encrypts, when required,the MCBCS content on application layer, and transfers the MCBCS contentin the format required by MCBCS session. The controller 144 of the MCBCSserver 140 assigns IP multicast address, authenticates the contentprovider 170, controls the MCBCS content transport between the contentserver 142 and content provider 170 and MCBCS bearer establishment andrelease, generates and distributes MCBCS security key including MAK andapplication layer encryption key, decides and controls MCBCS sessionstart and end, controls the MS 102 joining and leaving a certain MCBCS,authenticates and authorizes the MS 102 requesting for some MCBCS,maintains information about the MS 102 joined the MCBCS, collectsaccounting information and supports charging for the MS 102 and MCBCSprovider and ASNs, decides which ASNs need to multicast/broadcast theMCBCS according to the MCBCS information, MCBCS subscriber profile (e.g.profile of the MS's owner) and the MCBCS proxy list and knowledge ofwhole MCBCS transmission zone configuration. The session start, datapath registration, and subscription procedures for providing the MCBCSare described hereinafter.

FIG. 2 is a signaling diagram illustrating a session start and data pathregistration procedure in serving ASN of a communication systemaccording to an embodiment of the present invention. Herein FIG. 2 showsa session start and data path registration procedure in different ASN,when the MS 102 entered the anchor ASN through an initial network entryprocedure with the WiMAX system, and wants to be provided the MCBCSthrough the different ASN with the anchor ASN.

Referring to FIG. 2, if there is an MCBCS content corresponding to MCBCSto be provided to the MS 102 through the serving ASN, the MCBCS server140 assigns IP multicast address to multicast content for sessioninitiate, transmits a Session Start Request (Session_Start-REQ) message,including session information and QoS information corresponding to theMCBCS content, to the ASN GW1 120 of the serving ASN (S202).

Upon receipt of the Session_Start-REQ message, the ASN GW1 120 assignsan SFID, and transmits the Session_Start-REQ message to all BSs, i.e.BS1 112 and BS2 114, within the same MBS zone, which is provided sameMCBCS, together with a Resource Reservation Request (RR-REQ) message ora Data Path Registration Request (DP_REG-REQ) message (S204 and S206).The BSs 112 and 114 each transmit same MCBCS data, and the RR-REQmessage and DP_REG-REQ message can be transmitted by being piggybacked.At this time, a Generic Routing Encapsulation (GRE) tunnel is createdper service flow of the BSs 112, 114. The GRE tunneling is created sothat the same MCBCS data are transmitted to the MSs within the same MBSzone.

Herein, the Session_Start-REQ message transmitted by the ASN GW1 120includes MCID, air resource parameters between the MS 102 and the BSs112 and 114, and MAP information of MCBCS frame for providing MCBCS tothe MS 102. The MAP information of the MCBCS frame is a MAP informationof a MCBCS frame, transmitting the MCBCS data in MAC or PHY layers whenthe BSs 112 and 114 provide the MCBCS to the MS 102, and includes MBSburst frame offset, OFDMA symbol offset, subchannel offset, number ofOFDMA symbols, number of subchannels, Repetition Coding Indication, nextMBS frame offset, and next MBS OFDMA symbol offset. When the MCBCS datainformation to be transmitted within the serving ASN is received fromthe MCBCS server 140, the proxy module 124 of the ASN GW1 120dynamically creates the MCID and resource parameter for the MCBCS. TheMCID and resource parameters for the MCBCS also can be created by anElement Management System (EMS) of the WiMAX system and transmitted tothe ASN GW1 120.

The RR-REQ message transmitted by the ASN GW1 120 includes the SFID, IPmulticast address (e.g. MCID) for the BS1 112 and BS2 114, andparameters related to QoS. The DP_REG-REQ message includes informationrelated to data tunnel and QoS information.

Upon receipt of the Session_Start-REQ/RR-REQ/DP_REG-REQ message, each ofthe BSs 112 and 114 performs resource reservation and data pathregistration, and then each transmits a Session Start Response(Session_Start-RSP)/Resource Reservation Response (RR-RSP)/Data PathRegistration Response (DP_REG-RSP) message to the ASN GW1 120 (S208 andS210).

If the Session_Start-RSP/RR-RSP/DP_REG-RSP message each is received,then the ASN GW1 120 transmits the Session_Start-RSP message to theMCBCS server 140 (S212).

Upon receipt of the Session_Start-RSP message, the MCBCS server 140creates an R3 tunnel with the ASN GW1 120 for delivering the MCBCScontent (S214). At this time, the R3 tunnel can be created according tothe multicast routing protocol specified by the Internet EngineeringTask Force (IETF). In this manner, the session start procedure among theserving ASN (including the ASN GW1 120 and BSs 112 and 114), the MCBCSserver 160, and the MS 102 is successfully completed such that the datapath is registered. After the data path registration has completed, aservice announcement or service advertisement process is performed witha service selection process (S216).

As described above, in order to provide the MCBCS to the MS 102, theWiMAX system establishes a tunnel between the MS 102 and MCBCS server140 by exchanging messages among the MCBCS server 140, ASN GW1 120 ofthe serving ASN, and BSs 112 and 114, the messages includingSession_Start-REQ/RSP messages, RR-REQ/RSP messages, and DP_REG-REQ/RSPmessages, thereby completing session start and data path registrationand supporting to provide MCBCS to the MS 102.

FIG. 3 is a signaling diagram illustrating a subscription procedure of aMS in a communication system to an embodiment of the present invention.Herein FIG. 3, shows a subscription procedure of MS thorough an ASNafter completing the session start and data path registration procedurefor providing the MCBCS as described in FIG. 2. When the MCBCS isprovided with the multicast/broadcast scheme, the WiMAX system starts anactivation procedure of service flow for providing the MCBCS in networknon-related to an MCBCS provision request of the MS, in a case that theMS attempts to enter the network. That is, the WiMAX is that the MCBCSis activated at the network entry after the MS is successfullyauthenticated, but, the service flow of the MCBCS is not deactivatedwhen the MSr does not want to provided the MCBCS.

Referring to FIG. 3, as described in FIG. 2, after the start of thesession of the serving ASN, the data path registration, the serviceannouncement and selection (S216), the MS 102 performs a network entryprocedure to the AAA server 150 by initiate network entry (S302) andAccess Authentication procedure with the AAA server 150 (S304). Next,the SFA module2 136 of the anchor ASN transmits the serving BS (BS1 112)a Path Registration Request (Path_REG-REQ) message including ServiceFlow Information of the MCBCS to be provided to the MS 102 and MCBCSdata path information (S306). In order to simplify the explanation, itis assumed that the serving BS is BS1 112 among the BS1 112 and the BS2114.

Upon receipt of the Path_REG-REQ message, the BS1 112 performs a DynamicService Addition (DSA) procedure with the MS 102. That is, the BS1 112transmits the MS 102 a DSA Request (DSA-REQ) message (S308), and the MS102 transmits the BS1 112 a DSA Response (DSA-RSP) message in responseto the DSA-REQ message (S310). Here, the DSA procedure between the canbe repeated more than once when the number of MCBCS data is greater thanone, and the DSA-REQ message includes an MCID, an MBS zone ID, and aSFID.

After receiving the DSA-RSP message, the BS1 transmits a PathRegistration Response (Path_REG-RSP) message including the service flowinformation according to the DSA procedure and path information on theMCBCS data (S312). Upon receipt of the Path_REG-RSP message, the SFAmodule2 136 transmits a Path Registration Acknowledgement (Path_REG-ACK)message to the BS1 112 in response to the Path_REG-RSP message (S314).Accordingly, the subscription of the MS 102 and service flow creationfor the MCBCS to be provided through the serving ASN with which the datapath is registered are completed. A procedure for providing MCBCS withstatic multicast service scheme is described hereinafter.

FIG. 4 is a signaling diagram illustrating an MCBCS join procedure in acommunication system according to an embodiment of the presentinvention. FIG. 4 shows an MCBCS join procedure in a case in which an MSwithin the MBS zone is provided the MCBCS form the WiMAX system (e.g.the MS requests the WiMAX system for MCBCS join) with static multicastservice scheme.

Referring to FIG. 4, as described in FIG. 2, after the MCBCS sessionbetween the serving ASN (i.e. the ASN GW1 120 and the BSs 112 and 114)and the MCBCS server 160 and the MS 102, has started, the data path hasbeen registered, and the service announcement and service selection hasbeen done (S216), the MS 102 transmits an join initiate message (e.g.IGMP Join message) to the ASN GW2 130 of the anchor ASN with which theMS 102 has performed the initial network entry in order to be providedthe MCBCS from the WiMAX system providing the MCBCS with staticmulticast service scheme (S402). In the MCBCS join procedure forproviding the MCBCS with static multicast service scheme, the IGMP joinmessage can be received after the data path to provide the MCBCS hasbeen established in the ASN of the MS 102. The IGMP join messageincludes an IP multicast address of the MCBCS content which is providedto the MS 102. In a case that the WiMAX system operates with IGMPversion 3 (IGMPv3), the MS 102 transmits only one IGMP report messagefor joining multiple multicast groups. Otherwise, when the WiMAX systemoperates with IGMPv1 or IGMPv2, the MS 102 transmits multiple IGMPreport messages of same number as one of MCBCS content channel. Themultiple multicast groups are included in MCBCS program for providingthe MCBCS.

Upon receipt the IGMP join message, the ASN GW2 130 transmits a MCBCSrequest (MCBCS-REQ) message as the IGMP join message to the ASN GW1 120of the serving ASN by signaling (S404), such that the IGMP join messageis delivered. The MCBCS-REQ message includes the BS identifiers (BSIDs)of the BSs transmitting the MCBCS data to the MS 102 and Network AccessInformation (NAI) for the serving ASN.

Upon receipt of the MCBCS-REQ message, the ASN GW1 120 transmits anMCBCS Authentication and Authorization Request (MCBCS_AA-REQ) message tothe MCBCS server 140 for MCBCS authentication and authorization (S406).The MCBCS_AA-REQ message includes the IP multicast address and NAI. Ifthe ASN GW1 120 has already acquired an MCBCS subscription profile ofthe MS 102, the ASN GW1 120 performs the authentication andauthorization for the MS 102 by itself such that the MCBCS_AA-REQmessage transmission to the MCBCS server 140 (S406) is skipped.

If the ASN GW1 120 had not acquired the MCBCS subscription profile ofthe MS 102 and transmitted the MCBCS_AA-REQ message to the MCBCS server140, the MCBCS server 140 transmits an Access Request (Access-REQ)message to the AAA server 150 for authenticating and authorizing the MS102 (S408). If the Access-REQ message is received, then the AAA server150 performs authentication and authorization based on the profile ofthe MS 102, and transmits an Access Response (Access-RSP) messageincluding the authentication and authorization result to the MCBCSserver 140 (S410).

Upon receipt of the Access-RSP message, the MCBCS server 160 transmitsan MCBCS Authentication and Authorization Response (MCBCS_AA-RSP)message including the authentication and authorization result to the ASNGW1 120 (S412). As aforementioned, if the ASN GW1 120 has alreadyacquired the MCBCS subscription profile of the MS 102, theMCBCS_AA-REQ/RSP message exchange (S408 and S410) is skipped.

If the MCBCS_AA-RSP message is received, then the ASN GW1 120 transmitsan MCBCS Response (MCBCS-RSP) message to the ASN GW2 130 in response tothe MCBCS-REQ message (S414). And the ASN GW1 120 transmits to theserving BS (e.g. BS1 112) an MCBCS Join Request (MCBCS_Join-REQ) messageincluding the MCID corresponding to the MCBCS to be provided to the MS102, SFID, and IP multicast address (S416). In this embodiment, it isassumed that, among the BS1 112 and the BS2 114, the BS1 112 is theserving BS to the MS 102.

Upon receipt of the MCBCS_Join-REQ message, the BS1 112 performs aDynamic Service Addition (DSA) procedure with the MS 102. That is, theBS1 112 transmits a DSA Request (DSA-REQ) message to the MS 102 (S418),and the MS 102 transmits a DSA Response (DSA-RSP) message to the BS1 112in response to the DSA-REQ message (S420). The DSA-REQ message includesthe MCID, MCBCS Content ID, and MBS zone ID corresponding to the MS 102and the MCBCS be provided to the MS.

If the DSA-RSP message is received, then the BS1 112 transmits the ASNGW1 120 a MCBCS Join Response (MCBCS_Join-RSP) message including resultof which the DSA procedure is successfully performed (S422). Uponreceipt of the MCBCS_Join-RSP message, the ASN GW1 120 determines thatthe MCBCS join procedure of the MS 102 is successfully performed to theserving ASN, and recognizes that a provision of the MCBCS is availablefor the MS 102 according to a success of which the MCBCS join procedure.Also, the BS1 112 transmits a DSA Acknowledgement (DSA-ACK) message tothe MS 102 in response to the DSA-RSP message (S424). Upon receiving theMCBCS_Join-RSP message and being successfully performed the MCBCS joinprocedure of the MS 102, the ASN GW1 120 updates MCBCS context which isrelated to the MCBCS.

In this manner, if the MS 102 being provided the MCBCS transmits theIGMP Join message to the anchor ASN for joining the MCBCS to be providedthe MCBCS, the anchor ASN requests the serving ASN for the MS's MCBCSjoin, and the serving ASN (i.e. the ASN GW1 120, BS1 112), and MCBCSserver 140 support the MCBCS join of the MS 102 and provide the MCBCSwith static multicast service scheme.

FIG. 5 is a signaling diagram illustrating an MCBCS join procedure in acommunication system according to another embodiment of the presentinvention. FIG. 5 shows an MCBCS join procedure in a case in which theWiMAX system provide the MCBCS to the MBS zone with static multicastservice scheme non-related to the MCBCS join request of the MS (e.g.anchor ASN requests the MCBCS join for the MS) in the WiMAX systemproviding the MCBCS with static multicast service scheme.

Referring to FIG. 5, as described in FIG. 2, after the MCBCS sessionbetween the serving ASN (i.e. the ASN GW1 120 and the BSs 112 and 114)and the MCBCS server 160 and the MS 102, has started, the data path hasbeen registered, and the service announcement and service selection hasbeen done (S216), when MCBCS data is existed the MBS zone with multicastin the MBS zone, the ASN GW2 130 of the anchor ASN for the MS 102transmits an MCBCS-REQ message to the ASN GW1 120 of the serving ASN sothat the MCBCS join procedure is initiated for the MS 102 (S502). TheASN GW2 130 transmits the MCBCS-REQ message by signaling, the MCBCS-REQmessage includes the BSIDs of the BSs that are multicasting the MCBCSdata to the MS 102 and the NAI of the serving ASN.

Upon receipt of the MCBCS-REQ message, the ASN GW1 120 transmits theserving BS (BS1 112) an MCBCS_Join-REQ message including an MCID, SFID,and IP multicast address corresponding to the MS 102 and the MCBCS to beprovided to the MS 102 (S504). In this embodiment, it is assumed that,among the BS1 112 and BS2, the BS1 112 is the serving BS to the MS 102.

If the MCBCS_Join-REQ message is received, the BS1 112 performs a DSAprocedure with the MS 102. That is, the BS1 112 transmits a DSA-REQmessage to the MS 102 (S506), and the MS 102 transmits a DSA-RSP messageto the BS1 112 in response to the DSA-REQ message (S508). The DSA-REQmessage includes the MCID, MCBCS Content ID, and MBS zone IDcorresponding to the MS 102 and the MCBCS to be provided to the MS 102.

Upon receipt of the DSA-RSP message, the BS1 112 transmits the ASN GW1120 an MCBCS_Join-RSP message including result of which the DSAprocedure is successfully performed (S510), and transmits a DSA-ACKmessage to the MS 102 in response to the DSA-RSP message (S512). If theMCBCS_Join-RSP message received, then the ASN GW1 120 transmits the ASNGW2 130 of the anchor ASN an MCBCS Replay message including result ofwhich the MCBCS join procedure of the MS 102 is successfully performedto provide the MCBCS with static multicast service scheme in response tothe MCBCS-REQ message (S514). Upon receipt of the MCBCS_Join-RSPmessage, the ASN GW1 120 recognizes that a provision of the MCBCS isavailable for the MS 102 according to a success of which the MCBCS joinprocedure of the MS 102 is performed to the serving ASN. The ASN GW1 120received the MCBCS_Join-RSP updates the MCBCS context related to theMCBCS according to a success of which the MCBCS join procedure of the MS102 is performed, i.e. receipt of the MCBCS_Join-RSP message.

As aforementioned, in the WiMAX system, when the MCBCS is existed to beprovided to the MBS zone non-related to the MCBCS join request of the MS102, the anchor ASN requests the serving ASN for the MCBCS join of theMS 102, and the serving ASN (i.e. the ASN GW1 120, BS1 112) and MCBCSserver 140 support the MCBCS join of the MS 102, such that the WiMAXprovides the MCBCS with static multicast service scheme.

FIG. 6 is a signaling diagram illustrating an MCBCS leave procedure in acommunication system according to an embodiment of the presentinvention. FIG. 6 shows an MCBCS leave procedure in a case in which theMS, which having been provided the MCBCS by performing the MCBCS joinprocedure with the WiMAX system providing the MCBCS with staticmulticast service scheme as described in FIG. 4, does not want to beprovided the MCBCS form the WiMAX (e.g. the MS requests an MCBCS leave).

Referring to FIG. 6, when the MS 102, which having been provided theMCBCS from the WiMAX system with static multicast service scheme byperforming the MCBCS join procedure with the WiMAX system as describedin FIG. 4, does not want to be provided the MCBCS, the MS 102 transmitsan IGMP Leave message to the anchor ASN GW2 130, with which the MS 102performs initial network entry, in order to perform an MCBCS leaveprocedure (S602). At this time, the MS 102 transmits the IGMP leavemessage using an Initial Service Flow (ISF) or pre-provisioned serviceflow for leaving specific multicast service indicated by the IPmulticast address. That is, MS 102 transmits the IGMP leave messageincluding the IP multicast address of the MCBCS content wanted to leavethe MCBCS (i.e. stop providing the MCBCS) for leaving the MCBCS with theserving ASN.

Upon receipt of the IGMP leave message, the ASN GW2 130 transmits anMCBCS-REQ message to the ASN GW1 120 of the serving ASN (S604) bysignaling. That is, the IGMP Leave message is encapsulated in anMCBCS-REQ message. The MCBCS-REQ message includes BSIDs of the BSstransmitting the MCBCS data to the MS 102, an NAI of the serving ASN andthe IGMP Leave message.

Upon receipt of the MCBCS-REQ message, the ASN GW1 120 transmits to theMCBCS server 140 an MCBCS Leave Indication (MCBCS_Leave_IND) messageincluding signature of the MS 102 for MCBCS authentication consideration(S606). If the MCBCS_Leave_IND message is received, then the MCBCSserver 140 transmits an MCBCS Leave Response (MCBCS_Leave-RSP) messageto the ASN GW1 120 with verification and in response to theMCBCS_Leave_IND message (S608). The MCBCS_Leave-RSP message includes theNAI to the serving ASN of the MS 102 and the MCBCS indicator or MCBCSID. The MCBCS server stops updating the MCBCS related to context.

Upon receipt of the MCBCS_Leave-RSP message, the ASN GW1 120 transmitsan MCBCS Leave Request (MCBCS_Leave-REQ) message to the serving BS ofthe MS 102 (e.g. BS1 112) (S610). In this embodiment, it is assumedthat, among the BS1 112 and BS2 114, the BS1 112 is the serving BS ofthe MS 102. The MCBCS_Leave-REQ message can reuse the RR-REQ messageused in the session start and data path registration procedure asdepicted in FIG. 2. The MCBCS_Leave-REQ message includes the MCBCSindicator of the MCBCS to leave, corresponding SFID, and MCID.

Upon receipt of the MCBCS_Leave-REQ message, the BS1 112 performs aDynamic Service Deletion (DSD) procedure with the MS 102. That is, theBS1 112 transmits a DSD Request (DSD-REQ) message to the MS 102 (S612),and the MS 102 transmits a DSD Response (DSD-RSP) message to the BS1 112in response to the DSD-REQ message (S614). The DSD-REQ message instructsthe MS 102 to release the radio resource of MCBCS traffic correspondingto the MCBCS to leave.

Upon receipt of the DSD-RSP message, the BS1 112 releases, if the MS1102 is the last MS receiving the MCBCS traffic, the radio resourcecorresponding to the MCBCS traffic, and transmits the ASN GW1 120 anMCBCS Leave Response (MCBCS_Leave-RSP) message including the resourcelease result (S616). Consequently, the ASN GW1 120 received theMCBCS_Leave-RSP message completes the MCBCS leave procedure by deletingall contexts related to the MS 102, and releases connection with the MS102. That is, the ASN GW1 120 deletes all contexts related to the MS 102by receiving the MCBCS_Leave-RSP) message.

FIG. 7 is a signaling diagram illustrating an MCBCS leave procedure in acommunication system according to another embodiment of the presentinvention. FIG. 7 shows an MCBCS leave procedure in a case in which theWiMAX system having provided the MCBCS with static multicast servicescheme as depicted in FIG. 5, the MCBCS is not existed to be provided bythe WiMAX system (e.g. the MCBCS server requests an MCBCS leave).

Referring to FIG. 7, when MCBCS data is not existed to be provide to MBSzone by the WiMAX system, which having provided the MCBCS with staticmulticast service scheme by performing the MCBCS join procedure with theMS 102 as depicted in FIG. 5, the MCBCS server 140 transmits anMCBCS_Leave-REQ message to the ASN GW1 120 of the serving ASN (S702).Upon receipt of the MCBCS_Leave-REQ message, the ASN GW1 120 transmitsthe MCBCS_Leave-REQ message to all BSs (i.e. the BS1 112 and BS2 114)within the MBS zone defined by the MCBCS server 140 (S704 and S706).

Upon receipt of the MCBCS_Leave-REQ) message, each of the BSs 112 and114 performs a DSD procedure with all MSs within the MBS zone. That is,the serving BS (i.e. BS1 112) of the MS 102 transmits a DSD-REQ messageto the MS 102 (S708), and the MS 102 transmits a DSD-RSP message to theBS1 112 in response to the DSD-REQ message (S710). In this embodiment,it is assumed that, among the BS1 112 and the BS2 114, the BS1 112 isthe serving BS of the MS 102. The DSD-REQ message instructs the MS 102to release the radio resource of MCBCS traffic corresponding to theMCBCS to leave. Upon receipt of the DSD-RSP message, each of the BS1 112and BS1 14 releases the radio resource corresponding to the MCBCStraffic, if the MS performed the DSD procedure is the last MS receivingthe MCBCS traffic (particularly, the BS1 112 releases the radio resourcecorresponding to the MCBCS traffic receiving from the MS 102), andtransmits an MCBCS_Leave-RSP message including the radio resourcerelease result to the ASN GW1 120 (S712 and S714).

Upon receipt of the MCBCS_Leave-RSP message, the ASN GW1 120 deletes allcontexts related to the MS 102. The ASN GW1 120 also transmits theMCBCS_Leave-RSP message to the MCBCS server 140 in response to theMCBCS_Leave-REQ message (S716). The MCBCS server 140 received theMCBCS_Leave-RSP message deletes the MS information mapped by IPmulticast address. A method for providing MCBCS with dynamic multicastservice scheme is described hereinafter.

FIG. 8 is a signaling diagram illustrating an MCBCS join procedure in acommunication system according to another embodiment of the presentinvention. FIG. 8 shows an MCBCS join procedure in a case in which an MSwithin an MBS zone want to provide MCBCS form the WiMAX system, whichprovides the MCBCS with dynamic multicast service scheme based oncommunication environment, e.g. whether MS exist within the MCBCS zone(MS requests MCBCS join).

Referring to FIG. 8, after the service announcement and serviceselection procedure has successfully completed (S800), the MS 102transmits an IGMP Join message to the ASN GW2 130 of anchor ASN, withwhich the MS 102 has performed the initial network entry in order to beprovided the MCBCS from the WiMAX system providing the MCBCS withdynamic multicast service scheme (S802). Although the serviceannouncement and service selection procedure has performed, the sessionstart and data path registration procedures are not performed among theserving ASN (including the ASN GW1 120 and BSs 112 and 114), the MCBCSserver 160, and the MS 102 yet described in FIG. 2, but performed withthe MCBCS join procedure. That is, static MCBCS join procedure isperformed after the session starts and the data path is registered inMCBCS join with static multicast service scheme as depicted in FIG. 4,but in MCBCS join with dynamic multicast service scheme, the sessionstart and data path registration is performed with the MCBCS joinprocedure.

The IGMP Join message includes the IP multicast address of the MCBCScontent wanted to provide by the MS 102. In a cast that the WiMAX systemoperates with IGMPv3, the MS 102 transmits only one IGMP report messagefor joining multiple multicast groups. Otherwise, when the WiMAX systemoperates with IGMPv1 or IGMPv2, the MS 102 transmits multiple IGMPreport messages of same number as one of MCBCS content channel.

Upon receipt of the IGMP Join message, the ASN GW2 130 transmits aMCBCS-REQ message as the IGMP Join message to the ASN GW1 120 (S804) bysignaling. The MCBCS-REQ message includes the BSIDs of the BSstransmitting the MCBCS data to the MS 102, and NAI of the serving ASN.

Upon receipt of the MCBCS-REQ message, the ASN GW1 120 transmits anMCBCS_AA-REQ message to the MCBCS server 140 for MCBCS authenticationand authorization (S806). The MCBCS_AA-REQ message includes the IPmulticast address and NAI. If the ASN GW1 120 has already acquired anMCBCS subscription profile of the MS 102, the ASN GW1 120 performs theauthentication and authorization to the MS 102 by itself such that theMCBCS_AA-REQ message transmission (S806) is skipped.

If the ASN GW1 120 had not acquired the MCBCS subscription profile ofthe MS 102 and transmitted the MCBCS_AA-REQ message to the MCBCS server140, the MCBCS server transmits an Access-REQ message to the AAA server150 for authentication and authorization to the MS 102 (S808). Uponreceipt of the Access-REQ message, the AAA server 150 performsauthentication and authorization using profile of the MS 102, andtransmits the MCBCS server 140 an Access-RSP message including theauthentication and authorization result (S801).

Upon receipt of the Access-RSP message, the MCBCS server 140 transmitsthe ASN GW1 120 an MCBCS_AA-RSP message including the authentication andauthorization result (S812). Here, the MCBCS server 140 recognizes, onthe basis of the authentication and authorization result, that areceiver exists to receive the MCBCS within the MBS zone, transmits a PFserver 160 a Flow Info message including multicast IP, source IP andport, MCID, etc. (S814). The MCBCS server 140 may recognize that the MS102 is the first receiver to receive the MCBCS within the MBS zone basedon the authentication and authorization result. As aforementioned, whenthe ASN GW1 120 has already acquired the MCBCS subscription profile ofthe MS 102, the MCBCS_AA-REQ/RSP message exchange (S806 and S812), theAccess-REQ/RSP message exchange (S808 and S81), and the Flow Infotransmission (S814) are skipped.

Upon receipt of the MCBCS_AA-RSP message, the ASN GW1 120 transmits anMCBCS-RSP message to the ASN GW2 130 in response to the MCBCS-REQmessage (S816). Once the MCBCS-RSP message is received, the ASN GW2 ofthe anchor ASN and the MCBCS server 140 checks that the MS 102 is thefirst receiver to receive the MCBCS content through serving ASN withinthe MBS zone, i.e. the anchor ASN and the MCBCS server 140 checks thatthe MS 102 is the first receiver for the MCBCS content within the MBSzone (S818). As aforementioned, the MCBCS server 140, which provides theMCBCS with dynamic multicast service scheme, checks that the MS 102 isthe first receiver to receive the MCBCS within the MBS zone defined byitself. Also, the BS (BS2 114) belonged to the same MBS zone with theserving BS (i.e. BS1 112) checks that the MS 102 is the first receiverto provide the MCBCS within the MBS zone, for macro diversity of theMCBCS provided to the same MBS zone (S820). That is, the BS2 114 checksthat the MS 102 is the first receiver to receive the MCBCS within theMBS. In this embodiment, it is assumed that, among the BS1 112 and theBS2 114, the BS1 112 is the serving BS of the MS 102.

The PF server 160 received the Flow Info message transmits an RR-REQmessage to the ASN GW1 120 for reservation of resources required amongthe serving ASN, MCBCS server 140, AAA server 150, and PF server 160 inorder to provide the MCBCS being requested by MS 102 (S822). Uponreceipt of the RR-REQ message, the ASN GW1 120 assigns an SFID to beprovided the MCBCS by the MCBCS server 140 (i.e. to transmit the MCBCScontent to the MS 102 as the first receiver), and transmits the RR-REQmessage including the SFID, MCID, and IP multicast address to the BS1112 together with a DP_REG-REQ message (S824). At this time, the RR-REQmessage and DP_REG-REQ message are also transmitted to the BS2 114 formacro diversity. Here, the RR-REQ message and DP_REG-REQ message areused for session start and data path registration with the RR-RSPmessage and DP_REG-REQ message to be explained later. That is, theRR-REQ message and DP_REG-REQ message are transmitted for the data pathregistration and MCBCS join of the MS 102 and the RS-RSP message anddata path registration and success of MCBCS join for MCBCS is recognizedby the DP_REG-RSP message.

Upon receipt of the RR-REQ/DP_REG-REQ messages, the BS1 112 performs aDSA procedure with the MS 102. That is, the BS1 112 transmits a DSA-REQmessage to the MS 102 (S828), and the MS 102 transmits a DSA-RSP messageto the BS1 112 in response to the DSA-REQ message (S830). The DSA-REQmessage includes the MCID, MCBCS content ID, and MBS zone IDcorresponding to the MCBCS to be provided to the MS 102.

Upon receipt of the DSA-RSP message, the BS1 112 transmits the ASN GW1the RR-RSP and DP_REG-RSP messages including result of which the DSAprocedure is successfully performed, i.e. result of resource reservationand data path registration between the BS1 112 and the MS 102 to providethe MCBCS requested by the MS 102 (S832). Meanwhile, the BS2 114received the RR-REQ message and DP_REG-RSP message performs a resourceand registers a data path so that the MCBCS content is transmitted forthe macro diversity, and transmits the RR-RSP and DP_REG-RSP messagesincluding result of the resource reservation and data path registration(S384).

Upon receipt of the RR-RSP and DP_REG-RSP messages, the ASN GW1 120transmits the RR-RSP message to the PF server 160 in response to theRR-REQ message (S836). In the meantime, after transmitting theRR-RSP/DP_REG-RSP messages, the BS1 112 transmits a DSA-ACK message tothe MS 102 in response to the DSA-RSP message (S838). Consequently, theASN GW1 120 starts a session among the serving ASN (including the ASNGW1 120 and BSs 112 and 114), the MCBCS server 160, and the MS 102,registers the data path, and recognizes the MCBCS join of the MS 102.Here, the ASN GW1 120 received the RR-RSP and DP_REG-RSP messagesrecognizes that the session start and data path registration and MS'sMCBCS join procedures are successfully performed, and that a provisionof the MCBCS is available for the MS 102, and updates the MCBCS contextrelated to the MS 102, i.e. the MCBCS context related to the MCBCS byreceiving the RR-RSP and DP_REG-RSP message.

As described above, in the WiMAX system, the MS 102, which wants to beprovided the MCBCS, transmits an IGMP join message to anchor ASN forMCBCS join in order to be provided the MCBCS, and the anchor ASNrequests the serving ASN for the MCBCS join of the MS 102, the servingASN (i.e. the ASN GW1 120, BS1 112), and MCBCS server 140 support theMCBCS join of the MS 102, and provide the MCBCS with dynamic multicastservice scheme.

The MCBCS join procedure, to which the WiMAX system provides the MCBCSnon-related to the MCBCS join request of the MS in the WiMAX systemproviding the MCBCS with dynamic multicast service scheme, in acommunication system according to another embodiment of the presentinvention is performed in the same manner as the MCBCS join procedure,to which the WiMAX system provides the MCBCS non-related to the MCBCSjoin request of the MS in the WiMAX system providing the MCBCS withstatic multicast service scheme described in FIG. 5. Accordingly, theMCBCS join procedure in which the WiMAX system, providing the MCBCS withthe dynamic multicast service scheme, provides the MCBCS to MBS zone(e.g. anchor ASN) is performed same procedure in which the WiMAX system,providing the MCBCS with static multicast service scheme described inFIG. 5, detailed description about it is omitted.

FIG. 9 is a signaling diagram illustrating an MCBCS leave procedure in acommunication system according to another embodiment of the presentinvention. FIG. 9 shows an MCBCS leave procedure in a case in which theMS, which having been provided the MCBCS by performing the MCBCS joinprocedure with the WiMAX system providing the MCBCS with dynamicmulticast service scheme as described in FIG. 8, does not want to beprovided the MCBCS form the WiMAX (e.g. the MS requests an MCBCS leave).

Referring to FIG. 9, when the MS 102, which having been provided theMCBCS from the WiMAX system with dynamic multicast service scheme byperforming the MCBCS join procedure with the WiMAX system as describedin FIG. 8, does not want to be provided the MCBCS, the MS 102 transmitsthe ASN GW2 130 of its anchor ASN an IGMP Leave message, or a multicastgroup management protocol message (e.g. Multicast Listener DiscoveryLeave (MLD Leave) message) in order to perform the MCBCS Leave procedure(S902). At this time, the IGMP Leave message is transmitted using theISF or pre-provisioned service flow to release a specific multicastservice indicated by the IP multicast address. That is, the MS 102transmits the IGMP leave message including the IP multicast address ofthe MCBCS content be wanted to stop providing the MCBCS to MCBCS leavewith the serving ASN.

Upon receipt of the IGMP Leave message, the ASN GW2 130 transmits anMCBCS-REQ message as the IGMP Leave message to the ASN GW1 120 of theserving ASN by signaling (S904). The MCBCS-REQ message includes BSIDs ofthe BSs transmitting MCBCS data to the MS 102, NAI of serving ASN of theMS 102, and the IGMP Leave message.

Upon receipt of the MCBCS-REQ message, the ASN GW1 120 transmits theMCBCS server 140 an MCBCS_Leave_IND message including signature of theMS 102 for MCBCS authentication consideration (S906). Upon receipt ofthe MCBCS_Leave_IND message, the MCBCS server 140 transmits anMCBCS_Leave-RSP message to the ASN GW1 120 with verification and inresponse to the MCBCS_Leave_IND message (S908). The MCBCS_Leave-RSPmessage includes the NAI to the serving ASN of the MS 102, MCBCSindicator or MCBCS ID. The MCBCS server 140 stop updating the MCBCSrelated content.

Upon receipt of the MCBCS_Leave-RSP message, the ASN GW1 120 transmitsan MCBCS_Leave-REQ message to the serving BS (i.e. BS1 112) (S910). Inthis embodiment, it is assumed that, among the BS1 112 and BS2 114, theBS1 112 is the serving BS of the MS 102. The MCBCS_Leave-REQ message canreuse the RR-REQ message used in the session start and data pathregistration procedure. The MCBCS_Leave-REQ message includes the MCBCSindicator of the MCBCS to leave, corresponding SFID, and MCID.

Upon receipt of the MCBCS_Leave-REQ message, the BS1 112 performs a DSDprocedure with the MS 102. That is, the BS1 112 transmits a DSD-REQmessage to the MS 102 (S912), and the MS 102 transmits a DSD-RSP messageto the BS1 112 in response to the DSD-REQ message (S914). The DSD-REQmessage instructs the MS 102 to release the radio resource of MCBCStraffic corresponding to the MCBCS to leave.

Upon receipt of the DSD-RSP message, the BS1 112 releases, if the MS1102 is the last MS receiving the MCBCS traffic, the radio resourcecorresponding to MCBCS traffic, and transmits the ASN GW1 120 an MCBCSLeave Response (MCBCS_Leave-RSP) message including the resource leaseresult (S916). Here, the ASN GW1 received the MCBCS_Leave-RSP messagecompletes the MCBCS leave procedure by deleting all contexts related tothe MS 102, and releases the connection with MS 102. At this time, theASN GW2 130 of the anchor ASN checks whether the MS 102 released theconnection is the last MS providing the MCBCS content through theserving ASN within the MBS zone (S918). That is, the ASN GW2 130determines the MCBCS content to be transmitted to the MS 102 is the lastMCBCS content for the MS 102 and, if it is, the MCBCS server 140initializes the MCBCS.

Also, the ASN GW1 120 performs a data path deregistration procedure withthe BS1 120. That is, the ASN GW1 120 transmits a Path DeregistrationRequest (Path_DREG-REQ) message to the BS1 112 for deregistering thedata path registered in the MCBCS join procedure of FIG. 8 (S920), andthe BS1 112 transmits a Path Deregistration Response (Path_DREG-RSP)message to the ASN GW1 120 in response to the Path_DREG-REQ message(S922). Upon receipt of the Path_DREG-RSP message, the ASN GW1 120transmits a Multicast Tree Leave message to the MCBCS server 140 toleave the multicast tree (S924). Consequently, the MS 102, ASN GW1 120,and the MCBCS server 140 leaves the MCBCS, whereby the WiMAX systemstops providing MCBCS to the MCBCS zone.

If it is determined that the MS 102 released the connection is not thelast MS receiving the MCBCS content through the serving ASN at stepS918, i.e. there is at least one other MS receiving the MCBCS contenttransmitted by the ASN GW1 120, the ASN GW1 120 does not perform thedata path deregistration and transmission of the Multicast Tree Leavemessage.

FIG. 10 is a signaling diagram illustrating an MCBCS leave procedure ina communication system according to another embodiment of the presentinvention. FIG. 10 shows an MCBCS leave procedure in a case in which theWiMAX system having provided the MCBCS to MCBCS joining MS with dynamicmulticast service scheme as depicted in FIG. 8, the MCBCS is not existedto be provided by the WiMAX system (e.g. the MCBCS server requests anMCBCS leave).

Referring to FIG. 10, when MCBCS data is not existed to be provide toMBS zone by the WiMAX system, which having provided the MCBCS withdynamic multicast service scheme by performing the MCBCS join procedurewith the MS 102 as depicted in FIG. 8, the MCBCS server 140 transmits anMCBCS_Leave-REQ message to the ASN GW1 120 of the serving ASN (S1002).Upon receipt of the MCBCS_Leave-REQ message, the ASN GW1 120 transmitsthe MCBCS_Leave-REQ message to all BSs (i.e. the BS1 112 and BS2 114)within the MBS zone defined by the MCBCS server 140 (S1004 and 1006).

Upon receipt of the MCBCS_Leave-REQ message, each of the BS 112 and 114performs a DSD procedure with all MSs within the MBS zone. That is, theserving BS (i.e. BS1 112) of the MS 102 transmits a DSD-REQ message tothe MS 102 (S1008), and the MS 102 transmits a DSD-RSP message to theBS1 112 in response to the DSD-REQ message (S1010). In this embodiment,it is assumed that, among the BS1 112 and the BS2 114, the BS1 112 isthe serving BS of the MS 102. The DSD-REQ message instructs the MS 102to release the radio resource of MCBCS traffic corresponding to theMCBCS to leave. Upon receipt of the DSD-RSP message, each of the BS1 112and BS1 14 releases the radio resource corresponding to the MCBCStraffic, if the MS performed the DSD procedure is the last MS receivingthe MCBCS traffic (particularly, the BS1 112 releases the radio resourcecorresponding to the MCBCS traffic receiving from the MS 102), andtransmits an MCBCS_Leave-RSP message including the radio resourcerelease result to the ASN GW1 120 (S1012 and S1014).

Upon receipt of the MCBCS_Leave-RSP message, the ASN GW1 deletes allcontexts related to the MS 102. The ASN GW1 120 also transmits theMCBCS_Leave-RSP message to the MCBCS server 140 in response to theMCBCS_Leave-REQ message (S1016). The MCBCS server 140 received theMCBCS_Leave-RSP message deletes the MS (i.e. MS 102) information mappedby IP multicast address.

Next, the ASN GW1 112 of the serving ASN performs a data pathderegistration procedure with the BSs 112 and 114. That is the ASN GW1112 transmits a Path_DREG-REQ message to the BS1 112 and BS2 114 forrequesting deregistration of the data path registered in the MCBCS joinprocedure of FIG. 8 (S1018 and S1020), and each of the BS1 112 and BS2114 transmits the ASN GW1 112 a Path_DREG-RSP message includingderegistration result of the data path in response to the Path_DREG-REQmessage (S1022 and S1024). Upon receipt of the Path_DREG-REQ message,the ASN GW1 transmits a Multicast Tree Leave message to the MCBCS server140 for leaving from a multicast tree (S1026). Consequently, the datapath among the MCBCS server 140, serving ASN, and MS 102 is released,the WiMAX system stops providing MCBCS to the MBS zone. A method forproviding MCBCS to an MS with dynamic multicast service scheme in idlemode of the MS is described hereinafter.

FIG. 11 is a schematically diagram illustrating a structure of a WiMAXsystem for providing MCBCS to an MS in communication system according toanother embodiment of the present invention. FIG. 2 shows a structure ofa WiMAX system to provide the MCBCS with dynamic multicast servicescheme in idle mode of the MS.

Referring to FIG. 11, the WiMAX system is composed in the same structureas the WiMAX system depicted in FIG. 1 except that the ASN GW1 120 ofthe serving ASN includes a Path Control (PC) module1 128 for controllingdata paths of MSs, and the ASN GW2 130 of the anchor ASN includes a PCmodule2 138 for controlling data paths of the MSs within the WiMAXnetwork. When the MSs associated to the anchor ASN to which the PC 128(or 138) belonged move to another MCBCS zone, or operate in idle modewith the WiMAX system, or the MSs operating in idle mode move to anotherMCBCS zone, the PC modules 128 and 138 control the data paths of the MSsin the WiMAX system.

FIG. 12 is a signaling diagram illustrating a procedure for supportingthe MCBCS in a communication system according to another embodiment ofthe present invention. FIG. 12 shows an MCBCS support procedure in acase in which the WiMAX system the system checks an MS entering idlemode within an MBS zone providing MCBCS with dynamic multicast servicescheme and deregisters the data path between the serving BS and theanchor ASN.

Referring to FIG. 12, after the MCBCS subscription/Join procedure hasbeen successfully done (S1202), the MS 102 determines an idle mode entryinitiate to enter the idle mode (S1204), and transmits the serving BS(i.e. BS 112) a Deregistration Request (DREG-REQ) message indicating theidle mode entry initiate (S1205). In this embodiment, it is assumedthat, among the BS1 112 and the BS2 114, the BS1 112 is the serving BSof the MS 102.

Upon receipt of the DREG-REQ message, the BS1 112 transmits an Idle ModeEntry MS State Change Request (IM_Entry_MS_State_Change-REQ) message forrequesting change of the MS's state to the ASN GW2 130 of the anchor ASN(S1206) by entering the idle mode. At this time, the BS1 112 receivedthe DREG-REQ message is admitted to the idle mode entry by the anchorASN, transmits the ASN GW2 130 the IM_Entry_MS_State_Change-REQ messageso that parameters are acquired to enter the idle mode. TheIM_Entry_MS_State_Change-REQ message includes an ID of MBS zonecurrently existed the MS 102 and an ID of the serving ASN providing theMCBCS the MS 102.

Upon receipt of the IM_Entry_MS_State_Change-REQ message, the ASN GW2130 transmits the BS1 112 an Idle Mode Entry MS State Change Response(IM_Entry_MS_State_Change-RSP) message including paging information(e.g. paging group ID, paging cycle, and paging offset, etc) in responseto the IM_Entry_MS_State_Change-REQ message (S1208).

Upon receipt of the IM_Entry_MS_State_Change-RSP message, the BS1 112transmits a Deregistration/Re-registration Command (DREG_CMD) message tothe MS 102 in response to the DREG-REQ message (S1210). The DREG_CMDmessage has a path identifier field indicating position of the pagingcycle and paging offset which are assigned to MS 102 by the ASN GW2 130of the anchor ASN. Also, the BS1 112 received theIM_Entry_MS_State_Change-RSP message transmits an Idle Mode Entry MSState Change Acknowledgement (IM_Entry_MS_State_Change-ACK) message tothe ASN GW2 114 in response to the IM_Entry_MS_State_Change-RSP message(S1212). Next, the BS1 112 terminates the resource management with atime, and transmits the ASN GW2 130 a Path Deregistration Request(Path_DREG-REQ) message for requesting data path Deregistration byincluding recommended paging parameters (S1214).

Upon receipt of the Path_DREG-REQ message, the ASN GW2 130 deregistersthe data path corresponding to the service flow to the MS 102, andtransmits the BS1 112 a Path Deregistration Response (Path_DREG-RSP)message indication the data path deregistration in response to thePath_DREG-REQ message (S1216).

Upon receipt of the Path_DREG-RSP message, the BS1 112 transmits the ASNGW2 130 a Path Deregistration Acknowledgement (Path_DREG-ACK) message inresponse to the Path_DREG-RSP message (S1218). Consequently, the WiMAXsystem deregisters the data path for the MS 102, i.e. between the BS1112 and the anchor ASN, operates with the MS 102 in the idle mode.

As aforementioned, when the WiMAX system checks the MS 102 initiated theidle mode entry within the MBS zone providing MCBCS with dynamicmulticast service scheme, the WiMAX system deregisters the data path forthe MS, i.e. the data path established via the BS1 112 and the ASN GW2130 of the anchor ASN, thereby dynamically managing the data paths.

FIG. 13 is a signaling diagram illustrating a procedure for supportingthe MCBCS in a communication system according to another embodiment ofthe present invention. FIG. 13 shows an MCBCS support procedure in acase in which the WiMAX system the system checks an MS exiting from idlemode (e.g. entering active mode from idle mode) within an MBS zoneproviding MCBCS with dynamic multicast service scheme and registers thedata path between the serving BS and the anchor ASN of the MS.Particularly, FIG. 13 shows an MCBCS support procedure in a case inwhich the MS operating in the idle mode moves to another MBS zone andexits from the idle mode within the new MBS zone.

Referring to FIG. 13, as depicted in FIG. 8, after in a case when the MS102 performed the MCBCS Subscription and Join procedure (S1202) and thenoperating in idle mode through the Idle Mode Entry procedure (S1302)moves into another MBS zone, the MS 102 transmits its serving BS 1300 aRanging Request (RNG-REQ) message for registering a data path in the newMBS zone (S1304). That is, the MS 102 exits from the idle mode based ona paging from the new serving BS 1300, and transmits the serving BS 1300the RNG-REQ message indicating which the MS 102 attempts a networkre-entry. The RNG-REQ message includes the MCID and a Cipher MessageAuthentication Code (CMAC) associated with the MS 102.

Upon receipt of the RNG-REQ message, the serving BS 1300 checks that theMS 102 exits from the idle mode, and transmits the ASN GW2 130 of theanchor ASN an Idle Mode Exit MS State Change Request(IM_Exit_MS_State_Change-REQ) message for requesting change of the stateof the MS 102 (S1306).

If the IM_Exit_MS_State_Change-REQ message is received, then the ASN GW2130 fetches an authentication key for verifying the RNG-REQ message froman authentication module of the anchor ASN, and transmits the serving BS1300 an Idle Mode Exit MS State Change Response(IM_Exit_MS_State_Change-RSP) message in response to theIM_Exit_MS_State_Change-REQ message (S1308). Here, the ASN GW2 130performs authentication to the MS 102, which exits from the idle modeand attempts re-entry the network, using the authentication key.

Upon receipt of the IM_Exit_MS_State_Change-RSP message, the serving BS1300 triggers its data path, and transmits the ASN GW2 130 a PathRegistration (Path_REG-REQ) message for establishing a data path(S1310). That is, the serving BS 1300 requests the anchor ASN of the MS102 exited from the idle mode for requesting registration of the datapath by means of the Path_RE-REQ message.

Upon receipt of the Path_REG-REQ message, the ASN GW2 130 transmits theserving BS 1300 a Path Registration Response (Path_REG-RSP) messageconfirming the data path registration for the MS within the anchor ASN(S1312).

The serving BS 1300 received the Path_REG-RSP message transmits the MS102 a Ranging Response (RNG-RSP) message in response to the RNG-REQmessage (S1314). The RNG-RSP message includes information required foroccupying the service according to maintenance of the idle mode andinformation indicating success of the CMAC, particularly includes aHandover (HO) Process Optimization parameters required for handoverbetween MBS zones and REG-RSP TLV (Type, Length, and Value).

Once the RNG-RSP message is received, the MS 102 exits from the idlemode, and performs a network re-entry procedure with the ASN GW2 130(S1316). After the network re-entry procedure has successfullycompleted, the serving BS 1300 and the ASN GW2 130 of the anchor ASNupdate the CMAC key counter for the authentication module of the anchorASN and the MS 102, and the authentication module of the anchor ASNreceives the CMAC update for the MS 102 (S1318). Next, the serving BS1300 transmits the ASN GW2 130 a Path Registration Acknowledgement(Path_REG-ACK) message, indicating which the MS 102 completes networkre-entry procedure, in response to the Path_REG-RSP (S1320).

Finally, the ASN GW2 130 deletes the idle mode entry and context relatedto the MS 102, checks the previous MBS zone ID retained in the contextof the MS 102 (i.e. the MBS zone ID being controlled by the BS1 112) andthe serving ASN ID associated with the MBS being controlled by the BS1112), and transmits the ASN GW 1 120 a Leave Notification(Leave_Notification) message informing which the MS 102 moves to anotherMBS zone (S1322).

When the MBS zone ID retained in the context of the MS 102 (i.e. the MBSzone ID before the MS's movement) differs from the MBS zone IDassociated with the service BS 1300, the ASN GW2 130 transmits theLeave_Notification message to the ASN GW1 120. The ASN GW1 120 receivedthe Leave_notification message deletes the MS 102 moved to another MBSzone from the MCBCS MS list. Next, the ASN GW1 120 checks whether the MS102 is the last MS which is provided the MCBCS within the MBS zone ofthe ASN GW1 120. That is, the ASN GW1 120 checks whether the MS existsto be provided the MCBCS through ASN including the ASN GW1 120. If theMS does not exist to be provided the MCBCS, the ASN GW1 120 performs thedata path deregistration procedure of the data path established in theASN including the ASN GW1 120, deregisters all data path established forproviding the MCBCS content. Otherwise, if the MS exists to be providedthe MCBCS, the ASN GW1 120 does not perform the data path deregistrationprocedure.

As aforementioned, when the WiMAX system checks that the MS 102 exitsfrom the idle mode within an MBS zone being provided the MCBCS withdynamic multicast service scheme, the WiMAX system registers a data pathcorresponding to the MS 102 (i.e. data path between the serving BS 1300of the MS 102 and the ASN GW2 130 of the anchor ASN within MBS zone),and deregisters the data path of the MS 102 within the ASN of theprevious MBS zone. When there is no other MS within the old MBS zone,the WiMAX system deregisters all data paths registered for providing theMCBCS content within the ASN corresponding to the old MBS zone, wherebythe data paths are managed dynamically.

Although exemplary embodiments of the present invention have beendescribed in detail hereinabove, it should be clearly understood thatmany variations and/or modifications of the basic inventive conceptsherein taught which may appear to those skilled in the present art willstill fall within the spirit and scope of the present invention, asdefined in the appended claims.

The invention claimed is:
 1. A method for providing Multicast andBroadcast Service (MCBCS) in a wireless communication system,comprising: performing a session procedure including receiving a sessionstart request message from an MCBCS server if there is an MBS data tosend, transmitting data path request messages to base stations providingthe MCBCS to a mobile station and transmitting a session start responsemessage after data path establishment; receiving, at an anchor AccessService Network Gateway (ASN GW), a join initiate message from a mobilestation to be provided with an MCBCS based on service announceinformation; transmitting a join request message to a serving ASN GWupon receipt of the join initiate message at the anchor ASN GW;receiving the join request message and transmitting an access requestmessage to a server; and requesting, at a corresponding one of the basestations, to perform a dynamic service addition procedure with themobile station based on the join request message, wherein the sessionstart request message includes a multicast connection identifier, aservice flow identifier, resource parameters between the base stationsand the mobile station, and a MAP information of a MCBCS frame.
 2. Themethod of claim 1, wherein the join request message includes a multicastconnection identifier, a service flow identifier, and an InternetProtocol multicast address.
 3. The method of claim 1, wherein thedynamic service addition procedure comprises transmitting a dynamicservice addition request message to the mobile station, receiving adynamic service addition response message from the mobile stationaccording to the dynamic service addition request message, andtransmitting a dynamic service addition acknowledgement message to themobile station according to the dynamic service addition responsemessage.
 4. The method of claim 3, wherein the dynamic service additionrequest message includes a multicast connection identifier, a servicecontent identifier, and a service zone identifier corresponding to theMCBCS to be provided to the mobile station.
 5. The method of claim 1,wherein the join initiate message includes an Internet Protocolmulticast address of an MCBCS content.
 6. A method for providingMulticast and Broadcast service (MCBCS) in a wireless communicationsystem, comprising: performing a session procedure including receiving asession start request message from an MCBCS server if there is an MBSdata to send, transmitting data path request messages to base stationsproviding the MCBCS to a mobile station and transmitting a session startresponse message after data path establishment; receiving, at an anchoraccess service network gateway (ASN GW), a join initiate message from amobile station and transmitting a join request message to a serving ASNGW; checking, at the anchor ASN GW, if the mobile station is a firstmobile station within a multicast and broadcast service (MBS) zone uponreceipt of the join request message, an MCBCS content, and transmittinga resource reservation request according to the MCBCS content to acorresponding one of the base stations; performing, at the correspondingbase station, a dynamic service addition procedure with the mobilestation upon receipt of the resource reservation request; receiving, atthe anchor ASN GW, a leave message from the mobile station to stop beingprovided with the MCBCS; transmitting, at the anchor ASN GW, a leavingindication message to the serving ASN GW upon receipt of the leavemessage; receiving, at the serving ASN GW, a leave response message andtransmitting, if the mobile station is a last mobile station within anMBS Zone, a deregistration request to the corresponding base station;and performing, at the corresponding base station, a dynamic servicedeletion procedure with the mobile station upon receipt of a leaverequest message.
 7. The method of claim 6, wherein the resourcereservation request messages includes a multicast connection identifier,a service flow identifier, and an Internet Protocol Multicast addresscorresponding to the MCBCS.
 8. The method of claim 6, wherein the stepof performing the dynamic service addition procedure comprisestransmitting a dynamic service addition request message to the mobilestation, receiving a dynamic service addition response message from themobile station according to the dynamic service addition requestmessage, and transmitting a dynamic service addition acknowledge messageto the mobile station according to the dynamic service addition responsemessage.
 9. The method of claim 6, wherein the dynamic service additionrequest message includes a multicast connection identifier, a servicecontent identifier, and a service zone identifier corresponding to theMCBCS to be provided to the mobile station.
 10. The method of claim 6,wherein the join initiate message includes an Internet Protocolmulticast address of the MCBCS content to be provided to the mobilestation.
 11. A system for supporting Multicast and Broadcast Service(MCBCS), comprising: a mobile station, a base station, an Access Servicenetwork Gateway (ASN GW), an MCBCS server, and a policy server, whereinthe ASN GW comprises: a proxy module for supporting an assignmentfunction of multicast connection identifiers and radio resources, alayer 2 security function for MCBCS contents, a management function ofthe mobile station, resources for the MCBCS, a function of interworkingwith the policy server, a function of transmitting a Leave response ifthe mobile station is a last mobile station in a Multicast and BroadcastService (MBS) zone, and a function of triggering a dynamic serviceaddition procedure to the base station; and a Data Path Function (DPF)module for supporting registration and deregistration of a dynamic MCBCSdata path, and wherein the base station supports the layer 2 securityfunction and an MCBCS resource assignment function in a Media AccessControl (MAC) layer and an MCBCS resource assignment management functionin a Physical (PHY) layer, for the MCBCS contents.
 12. The system ofclaim 11, wherein the proxy module further supports an MCBCS groupmanagement function.